1. Field of the Invention
The present invention relates to an endoscope apparatus and a bending control method of an endoscope apparatus. More particularly, the present invention relates to an endoscope apparatus and a bending control method of an endoscope apparatus in which bending of a distal end of an insertion portion is controlled by controlling pressures applied to actuators that expand and contract by means of a fluid pressure.
2. Description of the Related Art
A large variety of endoscope apparatuses that insert an insertion portion into a subject and observe the inside of the subject have been conventionally available. In these endoscope apparatuses, a bending portion is provided at a proximal end of a distal end portion of the insertion portion, and the observation direction can be oriented in a desired direction by performing a bending operation with respect to the bending portion.
For example, among such endoscope apparatuses that include a bending portion, an endoscope apparatus has been proposed that, when bending the bending portion, causes the bending portion to bend by utilizing air pressure (for example, see Japanese Examined Patent Application Publication No. 6-67378).
In an endoscope apparatus that causes a bending portion to bend by utilizing air pressure in this manner, a gas supply source and an air chamber of the bending portion are connected to each other by a thin air tube, and the amount of bending is controlled by detecting a pressure of an actuator such as an artificial muscle by means of a pressure sensor that is provided in a connection portion between the air tube and an electromagnetic valve.